JPS60166434A - Gasifying device for slag of coal - Google Patents

Abstract

PURPOSE:To lower the temperature of a gasifying furnace, and to improve energy efficiency while effectively utilizing clinker formed by the gasifying furnace as a desulfuring agent by mixing limestone with coal and using the mixture as a raw material for the slag gasifying furnace. CONSTITUTION:A limestone supply pipe 12 is mounted to a gasifying furnace 1, and a piping system 11 supplying a desulfurizing tower 7 with clinker containing limestone from the gasifying furnace 1 is fitted. Coal in the gasifying furnace 1 is gasified, and ash in coal dissolves, and is changed into clinker together with CaO in limestone. Since an alkali component in ash increases and the viscosity of slag lowers by adding limestone to coal in the gasifying furnace 1, ash slag can be discharged smoothly even when the temperature of the gasifying furnace is lowered. Accordingly, the temperature of the gasifying furnace is lowered and the loss of sensible heat of a formed gas is reduced, and the energy efficiency of the whole gasifying furnace is improved while clinker produced in the gasifying furnace is utilized effectively as a desulfurizing agent.

Description

[Detailed Description of the Invention] (Field of Application of the Invention) The present invention relates to a coal slag gasification device, and more particularly to a coal slag gasification device that improves the energy efficiency of the entire gasifier and improves the effectiveness of a desulfurizing agent. be.

(Background of the Invention) In recent years, in order to diversify energy sources, there has been an urgent need to effectively utilize coal. Since coal, which is a solid fuel, is inconvenient to store and transport, various countries are developing technologies to gasify it and use it as a non-polluting gas fuel. Among these, in country a, the development of a high-calorie gasification process for gasifying coal to obtain feedstock gas or fuel gas and a low-calorie gasification process for gas production has been progressing, and more recently, Progress is also being made in developing a process in which coal is gasified in a spouted bed using oxygen and steam and the ash is discharged as slag.

This slag gasification process requires the establishment of a technology to melt and discharge the ash in the coal at a temperature within the furnace. There is a tendency for foreign coal to be used more frequently in the future, and a wide range of studies including Japanese coal are required. Therefore, in order to discharge the ash as slag, the temperature inside the furnace must be well controlled. In other words, in the case of coal with a low ash melting point, it is sufficient to reduce the amount of oxygen supplied per unit of coal, but in the case of coal with a high ash melting point, unless a large amount of oxygen is supplied, the temperature inside the furnace will not rise and the slag will grow. It will not drain smoothly. For this reason, if operating conditions change depending on the type of coal, operation becomes extremely difficult and can easily cause trouble.

On the other hand, in the slag gasification process, coal is gasified at high temperature and high pressure, so the produced gas is rich in carbon monoxide and hydrogen, and has the advantage of being able to be used for multiple purposes as a chemical raw material gas. In order to discharge the ash inside as slag, the temperature inside the furnace was increased from 1,500℃ to 2,000℃.
Therefore, the gasification reaction rate of carbon in coal is extremely fast, and the carbon utilization rate is close to 100%. However, since the temperature of the produced gas is extremely high, in order to increase the energy efficiency of the entire gasifier, it is necessary to minimize the sensible heat loss of this high-temperature gas.

The conventional slag gasification process, as shown in Figure 1,
Coal is supplied to the coal gasifier 1 from the supply pipe 2, and the supply pipe 3
a gasification step to obtain a generated gas to be reacted with a gasifying agent (oxygen, steam) supplied from the outlet pipe 10, a step of supplying the generated gas from the outlet pipe 10 to the high-temperature dust remover 5 to remove dust; It consists of a desulfurization step of supplying gas to the desulfurization Vi7 to remove sulfur compounds. The gas produced by the gasifier 1 contains dust containing unreacted char and sulfur compounds such as Has as harmful components. When harmful components such as Has are removed in the desulfurization tower 7 and the generated gas is purified at high temperature,
The energy efficiency of the entire process is high. In the desulfurization tower 7, desulfurization agents such as limestone, dotetramite, magnesium oxide, and iron oxide are usually used. Although it has been recycled and used repeatedly, in order to improve the energy efficiency of the gasifier, it is necessary to lower the gas temperature at the outlet of the gasifier as much as possible.

(Objective of the Invention) The object of the present invention is to reduce the viscosity of ash slag in a coal slag gasifier, lower the temperature of the entire gasifier, reduce sensible heat loss of the produced gas, and improve energy efficiency. Another object of the present invention is to provide a slag gasification device that can utilize ash slurry as a desulfurization agent.

(Summary of the Invention) The present invention provides a coal slag gasification apparatus having a gasification furnace for converting coal into slag gasification and a desulfurization device installed in the exhaust gas flow path, and a means for adding limestone to the gasification furnace. , CaO produced in the gasifier by adding the limestone
A piping system for supplying ash slag containing ash to the desulfurization device is provided.

(Example of the invention) Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 2 is a diagram showing a coal gasification treatment system according to an embodiment of the present invention. The difference from the device shown in Figure 1 above is that
A limestone supply pipe 12 is provided in the gasifier 1, and the gasifier 1
A piping system 11 is provided for supplying clinker containing limestone from the desulfurization tower 7 to the desulfurization tower 7. Coal to be gasified is supplied to the gasifier main body 1 from a coal supply pipe 2, and limestone is supplied from a limestone supply pipe 12, respectively. Coal is gasified in the gasifier 1 by oxygen and steam supplied from the gasifier supply pipe 3. Since the temperature of the gasifier is maintained at 1,500° C. or higher, the ash in the coal dissolves and becomes clinker together with CaO in the limestone.

The dust-containing gas generated in the gasifier 1 enters the high-temperature dust remover through the produced gas outlet pipe 10, and after dust is removed, it enters the desulfurization tower 7, where it is desulfurized and then exits the system from the outlet pipe 9. It is discharged outside.

On the other hand, the ash slag containing CaO produced in the gasifier 1 (
Clinker) enters the desulfurization tower 7 from the clinker supply pipe 11 and is used as a desulfurization agent for the generated gas. The waste clinker reacted in the desulfurization tower 7 is discharged from the system through the clinker discharge pipe 13, and is either reused or disposed of. The amount of clinker supplied to the desulfurization tower 7 can be controlled to an amount commensurate with the sulfur concentration in the exhaust gas.

Gasifier 10 By adding limestone to the coal, the alkaline component (CaO) in the ash increases and the slag viscosity decreases, so ash slag can be discharged smoothly even if the temperature of the gasifier is lower than before. Row 5 can be done.

Number 31 shows the results of measuring the melting point of ash when limestone is added to coal (Australian coal), and it is found that the melting point of ash drops by about 200°C when 5 grams of limestone is added and boiled.

According to the above embodiment, by adding limestone to the coal, the temperature of the gasifier can be lowered, the sensible heat loss of the produced gas is reduced, and at the same time, the supply of oxygen can be reduced.
The energy efficiency of the entire gasifier can be improved. In addition, clinker containing CaO produced in the gasifier,
It can be effectively used as a desulfurization agent that desulfurizes the generated gas at high temperatures. Furthermore, the natural limestone used conventionally was weak in strength and had a high pulverization rate, but the above-mentioned clinker had a very strong If and was found to have almost the same desulfurization performance as limestone. .

(Effects of the invention) As described above, by mixing limestone with coal and using it as a raw material for a slag gasifier, it is possible not only to lower the temperature of the gasifier and improve the energy efficiency of the entire gasifier. Clinker produced in the gasifier can be effectively used as a desulfurization agent.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional coal slag gasification process;
Fig. 2 is an equipment system diagram showing a coal slag gasification process according to an embodiment of the present invention, and Fig. 3 is a diagram showing a desulfurization performance curve when ash slag is used as the desulfurization agent in an embodiment of the present invention. be. 1... Gasifier main body, 2... Coal supply pipe, 3...
Gasifying agent supply pipe, 4... Ash extraction pipe, 5... High temperature dust remover, 6... Desulfurization agent supply pipe, 7... Desulfurization tower, 8...
Desulfurizing agent discharge pipe, 9... Purified gas outlet pipe, lO... Produced gas outlet pipe, 11... Clinker supply pipe, 12...
Limestone supply pipe, 13... clinker discharge pipe. Representative Patent Attorney Takenaga Kawakita Figure 3

Claims (1)

[Claims] (1) In a coal slag gasification apparatus having a gasification furnace for converting coal into slag gasification and a desulfurization device provided in the exhaust gas flow path, a means for adding limestone to the gasification furnace, and a means for adding limestone to the gasification furnace, and a means for adding limestone to the gasification furnace; A coal slag gasification apparatus characterized in that a piping system is provided for supplying ash slag containing CaO generated in a gasification furnace to the desulfurization apparatus.